In the food processing and packaging industry it is known to cut large pieces of foodstuff such as meat, into smaller, usually similarly sized, portions and then to pack the cut portions individually or more commonly in groups of two, three or more, for display (usually in chilled or frozen display cabinets) for selection by the public for purchase.
Thus pork and lamb are cut into chops, beef into steaks and bacon into thin slices. The cutting from the bulk product is often achieved using a rotating blade and the portions (i.e. chops or steaks) are allowed to fall one after another onto a moving conveyor belt.
An escapement mechanism may be provided so that the portions are separated along the length of the conveyor, and in general the portions will tend to fall in a similar way so that for example in the case of port chops the edge of each chop which is covered by a layer of fat may for example always be the leading (or trailing) edge of each chop in the line—depending on whether the bulk pork from which they are cut is fat side up or fat side down.
However there is no guarantee that the portions will be so aligned on the conveyor.
It is considered desirable for the portions (e.g. chops) which are to be presented in a so-called pre-pack, to all be aligned in a similar manner and either shingled (so that except for the topmost portion, those below are partly obscured by those above), or the portions are attractively arranged side by side on a flat tray, so that the size and quality of all of the portions making up the pack can be seen.
Hitherto the picking up and placing of portions into trays or other containers, has been at least in part performed manually. While this has meant that product orientation has not been called for on the conveyor, the process is labour intensive, and production limited to the speed at which the operators can pick and place the portions. The work is also tedious.
It is an object of the present invention to automate the above process.
It is another object to provide apparatus which can be employed in use to pick and place similar articles (which may be similar items of food but could be any similarly sized articles such as small manufactured items), which are to be packed for storage, and display for selling.
Existing Technology
Computer controlled robots have been developed and are available from ABB Ltd of Milton Keynes, England.
The IRB 340 and IRB 340SA robotic arms are especially suited to picking up foodstuff items such as pork or lamb chops, steaks, chicken portions, fish fillets and the like, elevating each picked up article so as to allow it to be moved laterally to another position (such as onto a parallel conveyor) where it can be lowered or dropped onto the other conveyor or onto a tray on the other conveyor.
During lifting, moving and lowering, the robot is adapted to be capable of rotating the article it has picked up, through up to 360° although for most purposes up to 180° of rotation in either direction from the position when it first engages the article, is sufficient.
To facilitate the positioning of the robot, video cameras, positioning sensors direction of movement and speed of movement transducers linked to each conveyor are provided to supply information to the controlling computer. In this way the arrival of the next article to be picked up by the robot can be flagged, its precise position across the width of the conveyor can be supplied to the computer, and if it is shaped (in plan view) or marked, so that its orientation can be visually determined, cameras viewing the articles can supply information which enables the computer to determine the precise orientation of each article and therefore determine by how much it needs to be rotated, so as to occupy a given orientation when positioned on the second conveyor (or in a tray thereon).
Where articles are stacked or shingled they can be picked and placed as one.
It is an object of the present invention to provide a tool (gripper) which can be mounted to and operated by such a robotic arm.